Digital TV receiving smart antenna control system and controlling method of the same

ABSTRACT

Disclosed is a digital TV smart antenna system and controlling method of the same, the system converges a smart antenna into an optimal reception by detecting a maximum signal power in a signal acquisition process for a fast acquisition performance and selectively assembling information such as signal power, multi-channel, SNR, and SER, and particularly, calculates signal power according to the antenna direction by fixing AGC as a specific value for detecting the maximum signal power.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Korean Application No.P2003-17197, filed on Mar. 19, 2003, which is hereby incorporated byreference as if fully set forth herein.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a digital TV, and moreparticularly, to a digital TV receiving smart antenna control system anda controlling method of the same.

[0004] 2. Discussion of the Related Art

[0005] Research about an antenna of a VSB (Vestigial Side Band) receiveris insufficient yet because it is an early stage, the antenna of the VSBreceiver selected as a standard transmitting method of terrestrialbroadcasting channel of a digital TV.

[0006] However, in recent years, a concept and an idea about the antennaare actively proposed. It is known that an ATSC (Advanced TelevisionSystems Committee) completed a standardization (CEA/EIA909) of theantenna.

[0007] An ATI (Next Wave) company experimentally applied the antenna toa real digital TV and currently a field test is ongoing. In other words,a TV market is at a beginning stage and technology of the digital TVreceiving antenna is also at the early stage.

[0008] There is technology of antenna applied to a radiotelecommunication system (For example, a cellular phone, militarywireless communication) in a related art. However, the technology isvery complex and expensive. Therefore, more technical efforts are neededfor applying the technology to the digital TV.

SUMMARY OF THE INVENTION

[0009] Accordingly, the present invention is directed to a digital TVreceiving smart antenna control system and a controlling method of thesame that substantially obviates one or more problems due to limitationsand disadvantages of the related art.

[0010] An object of the present invention is to provide a digital TVreceiving smart antenna control system and a controlling method of thesame for improving a receiving performance of a receiver in aterrestrial channel in poor and kaleidoscope surroundings by applying asmart antenna and an antenna control system to a digital TV receiver

[0011] Another object of the present invention is to provide a digitalTV receiving smart antenna control system and a controlling method ofthe same for improving quality of a receiving signal by removingmulti-channel at an indoor reception and improving the quality of thesignal through applying the smart antenna to a digital TV, and forproviding an excellent performance to transmitting towers at differentlocations.

[0012] Another object of the present invention is to provide a digitalTV receiving smart antenna control system and a controlling method ofthe same for detecting a maximum signal power direction at a high speedby detecting signal power at the high speed when a gain of the receiverin antenna control information is fixed at a predetermined level for anindoor reception, and by performing a 360° antenna scan by using thesignal power.

[0013] A further object of the present invention is to provide a digitalTV receiving smart antenna control system and a controlling method ofthe same for providing an optimal receiving signal to a digital TVreceiver by converging an optimal antenna direction by using an antennadirection tracing loop.

[0014] Additional advantages, objects, and features of the inventionwill be set forth in part in the description which follows and in partwill become apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

[0015] To achieve these objects and other advantages and in accordancewith the purpose of the invention, as embodied and broadly describedherein, a digital TV receiving smart antenna control system includes asmart antenna system for forming an antenna pattern suitable for signalreception by receiving mechanical or electrical antenna control signaland controlling a beam width, gain, and frequency characteristic, a VSBdemodulator for generating channel data for demodulating a VSB(Vestigial Side Band) signal received through the smart antenna system,generating channel data for the antenna pattern, and outputting thedemodulated VSB signal in a transport packet form, and an antennacontroller for receiving the channel data and auto gain controlinformation from the VSB demodulator and controlling the smart antennasystem by using the auto gain control information and the channelinformation set as a specific value.

[0016] In another aspect of the present invention, a digital TVreceiving smart antenna control system includes the smart antenna systemfor forming an antenna pattern suitable for signal reception byreceiving mechanical or electrical antenna control signal andcontrolling a beam width, gain, and frequency characteristic, a tunerfor tuning only a specific RF signal in RF (Radio Frequency) signalreceived through a smart antenna system, and converting the signal intoan IF signal after automatically controlling RF gain tuned according toRF gain control signal, a VSB (Vestigial Side Band) demodulator fordemodulating after controlling the IF (Intermediate Frequency) signalgain according to IF gain control signal, a channel information detectorfor detecting channel information such as signal power, multi-channelsignal power, SNR (signal-to-noise ratio), and SER (Segment Error Rate)outputted from the VSB demodulator, determining the channel conditionand outputting the channel information and the channel conditions, andan antenna direction acquisition controller for receiving signal powercondition, multi-channel signal power condition, SNR condition, SERcondition, and signal power information form the channel informationdetector and detecting and outputting an antenna direction of themaximum signal power, fixing the RF gain control signal and IF gaincontrol signal in acquisition process, and changing the signalsaccording to the receiving signal in a tracking process.

[0017] Meanwhile, a controlling method of a digital TV receiving smartantenna control system includes the steps of acquiring maximum signalpower according to the antenna direction by using signal powerinformation, multi-channel information, SNR information, and SERinformation extracted from an input signal, and converging the smartantenna into an optimal reception by selectively assembling the signalpower information, the multi-channel information, the SNR information,and the SER information.

[0018] It is to be understood that both the foregoing generaldescription and the following detailed description of the presentinvention are exemplary and explanatory and are intended to providefurther explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are included to provide afurther understanding of the invention and are incorporated in andconstitute a part of this application, illustrate embodiment(s) of theinvention and together with the description serve to explain theprinciple of the invention. In the drawings;

[0020]FIG. 1 illustrates a diagram showing a basic algorism of a digitalTV receiving smart antenna control system in accordance with the presentinvention.

[0021]FIG. 2 illustrates a block diagram showing a digital TV receivingsmart antenna control system in accordance with the present invention.

[0022]FIG. 3 illustrates a block diagram showing a first embodiment ofan auto gain controller of a VSB demodulator of FIG. 2.

[0023]FIG. 4 illustrates a block diagram showing a second embodiment ofan auto gain controller of a VSB demodulator of FIG. 2.

[0024]FIG. 5 illustrates a detailed block diagram showing a channelinformation detector of FIG. 2.

[0025]FIG. 6 illustrates a detailed block diagram showing a firstembodiment of a signal power information calculator of FIG. 3.

[0026]FIG. 7 illustrates a detailed block diagram showing a secondembodiment of a signal power information calculator of FIG. 3.

[0027]FIG. 8 illustrates a detailed block diagram showing a firstembodiment of a multi-channel signal power calculator of FIG. 3.

[0028]FIG. 9 illustrates a block diagram showing SNR informationcalculator of FIG. 3.

[0029]FIG. 10 illustrates a diagram showing an example of input/outputsignals of an antenna direction acquisition controller of FIG. 2.

[0030]FIG. 11 illustrates a detailed block diagram of an antennadirection acquisition controller of FIG. 2.

[0031]FIG. 12 illustrates a flow diagram of an antenna directionacquisition controller of FIG. 2.

[0032]FIG. 13 illustrates a flow diagram of an example of a timer ofFIG. 11.

[0033]FIG. 14 and FIG. 15 illustrate a flow diagram of an antenna scanprocessor of FIG. 11.

[0034]FIG. 16 illustrates a detailed block diagram of an antennadirection tracking controller of FIG. 2.

[0035]FIG. 17 illustrates a detailed block diagram of an antennadirection power tracking error detector of FIG. 16.

[0036]FIG. 18 illustrates a detailed block diagram of an antennadirection multi-channel power tracking error detector of FIG. 16.

[0037]FIG. 19 illustrates a detailed block diagram of an antennadirection SNR tracking error detector of FIG. 16.

[0038]FIG. 20 illustrates a detailed block diagram of an errorintegrator of FIG. 16.

DETAILED DESCRIPTION OF THE INVENTION

[0039] Reference will now be made in detail to the preferred embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

[0040] In the present invention, a receiving performance of a receiveris improved in a terrestrial channel in poor and kaleidoscopesurroundings by applying a smart antenna and an antenna control systemto a digital TV receiver. In other words, by optimizing the antennasystem, reliability of the receiver is improved.

[0041] The present invention has a characteristic of coping with anenvironment wherein a transmitting tower exists at different locationsaccording to a broadcasting channel. In fact, this is a matter of afrequent occurrence in other countries.

[0042] In general, because the digital TV receiver requires a limitedstable time, and a signal power detecting time takes up a long time inan antenna control process, the signal power detecting time is animportant factor influencing an acquisition performance of the system.

[0043] A general early acquisition time of a smart antenna is objectedto be less than one minute. To satisfy the limitation, a fast antennadirection acquisition performance is needed, which is an importantperformance factor of the smart antenna.

[0044] Together with this, the digital TV receiver detects a SNR(signal-to-noise ratio), multi-channel signal information, SER (segmenterror rate) for understanding quality of a receiving signal, and ittakes a long time to detect the SNR, multi-channel signal information,and SER.

[0045] Therefore, for fast acquisition performance, maximum signal poweris detected in a signal acquisition process and the smart antenna isconverged by selectively detecting signal power, multi-channel, SNR, andSER in a tracking process. Particularly, for detecting the maximumpower, the AGC (auto gain controller) is fixed at a predetermined valueand calculates signal power according to an antenna direction. In thetracking process, by continuously detecting channel information, thesmart antenna is controlled corresponding to a channel environmentchanging every hour.

[0046] Hereinafter, the digital TV receiving antenna control system andthe controlling method of the same will be described in reference toappended drawings. FIG. 1 illustrates a conceptional diagram showing abasic algorism of a digital TV receiving smart antenna control system inaccordance with the present invention.

[0047] As illustrated in FIG. 1, a basic concept of the antenna controlalgorism of the control system is that an optimal antenna direction isdetermined by acquiring the signal power at a predetermined degree (forexample, −180°, −90°, 0°, 90°, 180°) through 360° scanning of the smartantenna and by acquiring a maximum signal power location throughconverging the signal power to the antenna direction tracking loop in apredetermined degree unit.

[0048]FIG. 2 illustrates a block diagram of a digital TV receiving smartantenna control system including a smart antenna system 101, a VSBmodulator 102, and an antenna controller 103. First, the smart antennasystem 101 controls a beam width, a gain, a frequency characteristic bya mechanical or electrical antenna control signal of the antennacontroller 103 for an optimal antenna pattern for a signal reception.

[0049] The VSB modulator 102 includes an AGC, a symbol/carrier/syncrecoverer, a channel equalizer, a channel decoder (for example, FEC:forward error correction) and modulates the VSB signal received throughthe smart antenna system 101 for outputting in a transport packet form.In this case, the AGC method of the digital TV receiver is the same asillustrated in FIG. 3 and FIG. 4. *

[0050] The AGC method illustrated in FIG. 3 is a method of removing gainof IF signal of IF (Intermediate frequency) AGC 402 through the chargepump and filter 404 at the VSB receiving chip and removing gain of RF(Radio frequency) signal of a tuner 401 by using a delayed AGC signal.In the AGC method illustrated in FIG. 4, the gains of the IF signal andthe RF signal are directly removed at the VSB receiving chip 503.

[0051] In other words, the AGC method for directly removing the gains ofthe IF signal and the RF signal includes the steps of generating IF AGCcontrol signal and RF AGC control signal by using a passband or basebandreceiving signal modulated with the RF AGC reference value at the VSBreceiving chip 503, and outputting each signal to IF AGC 502 and a tuner01.

[0052] The IF AGC 502 changes the gain of the IF signal into a desiredstate by increasing or decreasing the gain of IF signal according to theIF AGC control signal inputted from the IF AGC 502 and the tuner 501changes the gain of the RF signal by increasing or decreasing the gainof the RF signal according to the RF AGC control signal.

[0053] Meanwhile, the antenna controller 103 controlling the smartantenna system 101 mechanically or electronically through the channeldata includes a channel information detector 103-1, an antenna directionacquisition controller 103-2, and an antenna direction trackingcontroller 103-3.

[0054] 1) Channel Information Detector:

[0055] The channel information detector 103-1 detects channel data (forexample, AGC information, modulated I channel data, phase tracked Ichannel data, FEC error data, Field sync signals), determines thechannel condition, and outputs the detected channel information and thechannel conditions to the antenna direction acquisition controller 103-2and the antenna direction tracking controller 103-2.

[0056] For this, the channel information detector 103-1, as illustratedin FIG. 5, includes a signal power detector 201 for outputting thesignal power information and the power condition, a multi-channel signalpower detector 203 for outputting the multi-channel signal powerinformation and condition, a SNR detector 203 for outputting the SNRinformation and SNR condition, and a SER detector 204 for outputting theSER information and the SER condition.

[0057] The signal power detector 201 includes a signal power informationcalculator 201-1 for detecting the signal power information from the IFgain and the RF gain, and a comparer 201-2 for comparing the signalpower information with a set signal power value and outputting thesignal power condition.

[0058] The multi-channel signal power detector 202 includes a signalpower information calculator 202-1 for detecting the multi-channelsignal power information from the equalizer input I channel dataoutputted from the demodulator 102 or the field sync signal, and acomparer for comparing the multi-channel signal power information withthe set multi-channel signal power reference value so as to output themulti-channel signal power condition.

[0059] The SNR detector 203 includes a SNR information calculator(203-1) for detecting the SNR information from the FEC input I channeldata or the field sync signal, and a comparer 203-2 for comparing theSNR information with the set SNR reference value so as to output the SNRcondition.

[0060] The SER detector 204 includes a SER information calculator 204-1for detecting SER information from a FEC error value outputted from thedemodulator 102, and a comparer 204-2 for comparing the SER informationand the set SER reference value so as to output the SER condition.

[0061] In this case, in the smart antenna control system, as illustratedin FIG. 4, the auto gain controller is provided to the VSB demodulator102 and gain control value (i.e., RG AGC control signal, IF AGC controlsignal) of the auto gain controller is set to a predetermined value inthe antenna direction acquisition process, so as to detect the signalpower by using the signal power detector illustrated in FIG. 6 or inFIG. 7.

[0062] In this instance, in the signal acquisition process of theantenna, a specific value for fixing the auto gain controller in FIG. 4is obtained experimentally through an experiment. In the presentinvention, as an embodiment, the auto gain control value with the bandpower of the input RF signal about 60 dbm is used for fixing the gaincontroller.

[0063] Hereinafter, the signal power information calculator 201-1included in the channel information detector 103-1, the multi-channelinformation calculator 202-1, the SNR information calculator 203-1, andthe SER information calculator 204-1 are described in detail.

[0064] 1-1) Signal Power Information Calculator:

[0065] The signal power information calculator 201-1 is realized in twomethods as illustrated in FIG. 6 and FIG. 7. In a first method, thesignal power information calculator 201-1 includes a squaring operator601 for receiving a passband or baseband I signal from the VSBdemodulator 102 for obtaining a squared value, and an integrator 602 foraccumulating the squared value into a predetermined window size fordetecting the signal power as illustrated in FIG. 6.

[0066] In other words, the squared operator 601 receives the passband orbaseband I signal from the VSB demodulator 102, obtains the squaredvalue and outputs the value to the integrator 602. The integrator 602accumulates the squared value into a predetermined size and divides theaccumulated value into a window size and outputs the value. The outputof the integrator 602 is the signal power information.

[0067] In a second method, the signal power calculator 201-1 detects thesignal power information by using an absolute value operator 701 and anintegrator 702 as illustrated in FIG. 7. In other words, the absolutevalue operator 701 receives the passaband and baseband I signal from theVSB demodulator 102, obtains the absolute value, and outputs the valueto the integrator 702. The integrator 702 accumulates the squared valueinto a predetermined size and divides the accumulated value into awindow size and outputs the value as the signal power information.

[0068] In this instance, in the antenna direction acquisition process,the gain control value of the auto gain controller of FIG. 4 is fixedinto a specific value and detects the signal power by using the signalpower detector 201.. And then, when the antenna direction acquisitionprocess is finished and the antenna direction tracking process isstarted, the auto gain controller forms a loop for controlling the autogain control amplifier and detects the signal power from the portion(integrator) storing the gain error in the loop.

[0069] 1-2) Multi-Channel Signal Power Information Calculator:

[0070] The multi-channel signal power calculator 201-1 detects themulti-channel signal power information by using the field sync sectionas illustrated in FIG. 8. In other words, a degree of the ghost incontradiction to a main signal is calculated.

[0071] In this case, two detecting methods are proposed. First, relativemulti-channel information is detected on a basis of correlation value ofthe field sync signal when the multi-channel does not exist by usingonly the field sync signal of the main signal (nFSYNC). In other words,the multi-channel power information is detected by a train sequencegenerator 801 for detecting train sequence from the field sync signal ofthe main signal, a multiplier 802-1 for multiplying the output signaland input signal of the train sequence generator 801, an integerextractor 803-1 for obtaining only integers from the output of themultiplier 802-1, and a ghost power formalizer 804 for calculating andformalizing ghost power from the output of the integer extractor 803-1so as to detect the multi-channel power information.

[0072] Second, correlation value between the field sync signal of themain signal (nFSYNC) and the field sync signal of the multi-channelsignals (gFSYNC) is calculated for finding the multi-channelinformation. In other words, the multi-channel information is found byusing a train sequence generator 801 for generating train sequence ofthe main signal and of each multi-channel signal from the field syncsignals of the main signal and the multi-channel signals (nFSYNC)(gFSYNC), number of multipliers (802-1, 802-2, . . . , 802-n) formultiplying the main and each multi-channel train sequence outputtedfrom the train sequence generator 801 with an input signal, n number ofinteger extractors (803-1, 803-2, . . . , 803-n) for extracting only theinteger from each output of the n number of multipliers (802-1, 802-2, .. . , 802-n), and a ghost power formalizer 804 for calculating andformalizing ghost power from the output of the n number of integerextractors (803-1, 803-2, . . . , 803-2).

[0073] Therefore, in the method of using tab coefficient or tab energyof a conventional convergence of the channel equalizer is preconditionand the information detection is possible in only a limited environment.However, in the method of using the multi-channel information from amulti-channel signal power information calculator 202-1 proposed by thepresent invention, the by detecting the multi-channel information of thechannel equalizer, the limitation is relieved.

[0074] 1-3) SNR Information Calculator:

[0075]FIG. 9 illustrates a block diagram showing SNR informationcalculator in FIG. 3. The following two methods are selectively used.

[0076] In a first method, that is a method of detecting error form fieldsync signal of demodulated receiving signal, an MSE (mean square error)value is calculated from the received field sync signal and the trainsequence and the SNR is calculated by using the MSE value. In thismethod, data is renewed in each field through detecting the error fromthe field synchronized portion of the demodulated receiving signal. Inthis case, a subtractor 901 calculates difference between the receivedsync signal and the training sequence.

[0077] In a second method, the MSE value is calculated from demodulatedand equalized I channel data (R_1) and decision constellation data(D_I), and the SNR is calculated from the MSE value. In other words, asa method of detecting error of the equalized I channel data and decisionconstellation value, data is renewed in each window of the accumulator.In this case, the subtractor 901 calculates the difference between the Ichannel data (R_1) and the decision constellation data (D_I), andoutputs the calculation to the multiplier 902.

[0078] Then, the multiplier 902 multiplies the output of the subtractor901 and outputs the calculation to the accumulator 903 for anaccumulation. The accumulator 903 temporarily stores the accumulatedsignal through a latch 904 and outputs to a modulo-operator 905. Themodulo-operator 905 counts the output of the latch 904 and resets thecounted value to 0 whenever the value is m. In this instance, the m is awindow size inputted to the accumulator 903.

[0079] The SNR is expressed in a following formula (1).

SNR=10·log(Ps/Pn)   (1)

[0080] If, Ps is formalized as 1,${{Pn}_{mse}} = {\sum\limits_{k = 1}^{k = n}{\left( {{mse}/m} \right).}}$

[0081] In this case, mse=(D_I−R_I)^(2,) R_I is received constellations,D_I is decision constellations, m is a window size of the accumulator.

[0082] 1-4) SER (Segment Error Rate)

[0083] The SER information calculator 204-1 receives the SER informationfrom the VSB demodulator 102 and detects the Segment Error Rate. The SERinformation is reliable information and becomes a basis of finaldetermination for antenna convergence result.

[0084] 2) Antenna Direction Acquisition Controller:

[0085] The antenna acquisition controller 103-2 receives channelcondition information (i.e., signal power condition, multi-channel powercondition, SNR condition and SER condition) and signal power informationfrom the channel information detector 103-1 and acquires the antennadirection.

[0086]FIG. 10 illustrates a diagram showing input/output signals of theantenna direction acquisition controller 103-2. In other words, asaforementioned, the input signal includes the channel conditioninformation, signal power information, and SYNCLOCK signals (Nsynclock)before EQ and before FEC of the channel equalizer.

[0087] While the antenna scans, the output signal outputs an EQfreezecontrol signal for suspending update of the channel coefficient, anEQ_freeze control signal for maintaining the early coefficient value byresetting when the channel equalizer is diverged, a track_en controlsignal for starting the antenna direction tracking process after theantenna acquisition process, an Ant_bw control signal for controlling astep size of the antenna direction by referring the channel conditioninformation (i.e., SNR, SER), a rescan control signal for initializingthe VSB demodulator 102 for reacquiring the antenna direction, an L_ensignal for notifying each delayed time satisfied at the timer, and anantenna direction acquisition signal.

[0088]FIG. 11 illustrates a detailed block diagram of an antennadirection acquisition controller in FIG. 2. As illustrated in FIG. 11,the antenna direction acquisition controller 103-2 includes an antennascan processor 1102, a timer 1101, an antenna pattern counter register1103, a signal power register 1104, a maximum signal power register1105, and an antenna direction acquisition register 1106, and realizedwith hardware or software according to necessity. The structure has anadvantage that flexibility of the system is largely increased. Functionof the antenna direction acquisition controller 103-2 is schematicallydescribed as follows.

[0089] The antenna direction acquisition controller 103-2 detects theantenna direction of the maximum signal power by receiving the signalpower information from the channel information detector 103-1 andtransmits the information to the antenna direction tracking controller103-3. The gain value of the auto gain controller of FIG. 4 is fixed asa specific value and the channel equalizer is stopped. After this, whenthe acquisition process is finished, the auto gain controller and thechannel equalizer are normally operated.

[0090] The antenna direction controller 103-2 receives each SYNCLOCKsignal (Nsynclock) from the before EQ and the before FEC of the channelequalizer, determines an initialization of the channel equalizer,watches and prevents the divergence of the channel equalizer because thechannel equalizer may be diverged when the antenna is scanned. Forexample, it is viewed that the equalizer is diverged if the sync isfound at the before the channel equalizer and not found at the beforeFEC for a predetermined time.

[0091] Movement of the antenna direction acquisition controller 103-2structured as mentioned above is described as follows. FIG. 12illustrates a flow diagram showing a whole process of an antennadirection acquisition controller in FIG. 2.

[0092] 1. The auto gain controller is fixed as a specific value(S2501-S2502).

[0093] 2. The antenna direction is rotated to 360° and confirms whetherthe receiving signal exists (S2503-S2508).

[0094] 3. The antenna is rotated to 360° from the direction of thereceiving signal for acquiring the maximum signal power direction(S2509-S2514).

[0095] 4. The antenna tracking process is started after acquiring themaximum signal power direction (S2515-S2519).

[0096] 5. Reception is watched by reading the channel conditioninformation (S2519).

[0097] 6. When the receiving condition is bad, the reacquisition processis prepared and the process of the step 1 is repeated (S2520-S2521).

[0098] Hereinafter, the antenna direction acquisition controller 103-2is described in more detail.

[0099] 2-1) Registers:

[0100] The antenna pattern count register 1103 counts pattern number ofthe smart antenna acquired during the antenna acquisition process, thesignal power register 1104 temporarily stores the signal powerinformation, the maximum signal power register 1105 stores the maximumsignal power value and the antenna direction, the antenna register 1106stores the antenna direction information at the maximum signal power andoutputs the antenna direction acquisition.

[0101] 2-2) Timer:

[0102] The timer 101 calculates the delay time of each the process ofthe scan processor 1102. In this case, the flow diagram calculating thedelay time for each process is illustrated in FIG. 13. As illustrated inFIG. 13, the delay time being a variable determined by environment andcondition id programmed at the timer 1101.

[0103] First, the variables being employed in FIG. 13 is defined asfollows. Agc_set_cnt is a delay time for fixing the auto gain controllerduring the acquisition process, Ant_set_cnt is a delay time for settingthe selected antenna pattern, Scan_set_cnt is a delay time for detectingthe signal power from the input signal, Rx_set_cnt is a delay time ofthe receiver for converging, Con_set_cnt is a delay time for detectingthe channel condition information, rescan_set_cnt is a delay time forreacquiring process, and L_en is a signal notified by the timer fornotifying each delay time is satisfied when 1.

[0104] Hereinafter, the movement of the timer 110 will be described.First, the timer initializes the variables in FIG. 13 (S1301), upon thedelay time (L_en=Agc_set_cnt) for fixing the auto gain control valueduring the acquisition process, checks the delay time for setting thecurrently selected antenna pattern (S1303-S1304), and checks the delaytime for detecting the signal power inputted from the input signal(S1305-S1306), and then checks whether all the set antenna patterns arescanned (S1307). If the timer determines that all the set antennadirections are not scanned, the timer scans a next antenna direction (Si308) and returns to the step 1303 (S1303).

[0105] Meanwhile, if the timer determines that all the set antennadirections are not scanned, the timer checks time for recovering thesystem (S1309-SI 310) and checks the delay time (Con_set_cnt) consumedfor detecting the channel condition information. When the channelcondition abovementioned is all satisfied (SI 1313), the timer checksthe delay time (rescan_set_cnt) consumed for reacquiring process(S1314-S1315).

[0106] 2-3) Antenna Scan Processor:

[0107] The antenna scan processor 1102 outputs control signals neededfor the acquisition process by receiving the signal power informationand the channel condition information (i.e., the signal power condition,multi signal power condition, SNR condition, and SER condition). In thiscase, the control signals of the scan processor 1102 in FIG. 14 to FIG.7 are as follows.

[0108] First, as an internal control signal of the antenna scanprocessor 1102, (1) cnt_rst initializes the antenna pattern counterregister 1103 when the cnt_rst is 1, (b) cnt is the antenna counterpattern value, (c) cnt_en allows counting of the antenna pattern counterregister 1103 when the cnt_en is 1, (d) max_pw_rst initializes themaximum signal power when the max_pw_en is 1, (e) max_pw_en allows renewof the maximum signal power register value 1105 when max_pw_rst is 1,(f) offset_cnt_en allows renew of the antenna direction acquisitionregister value 1106, (g) max_cnt_en allows loading the maximum signalpower antenna acquisition value from the maximum signal power register1105 to the antenna direction acquisition register 1106 when themax_cnt_en is 1. In the mean time, as an external control signals of theantenna scan processor 1102, (h) track_en allows the antenna directiontracking process after finishing the antenna acquisition process whenthe track_en is 1, (i) ant_bw controls a step size of the antennadirection by looking at the channel condition information (i.e., SNR,SER), (j) agc_fz fixes the auto gain controller (AGC) in the process ofthe antenna direction process when the agc_fz is 1, (k) rescaninitializes the VSB demodulator 102 for reacquiring the antennadirection when rescan is 1, (l) L_en is a signal for notifying that eachdelay time is satisfied at the timer 1101 when the L_en is 1.

[0109] Based on the control signal abovementioned, movement of theantenna scan processor 1102 illustrated in FIG. 14 and FIG. 15 isdescribed as follows.

[0110] First, the maximum signal power register 1105 and the antennapattern counter register 1103 are initialized and the auto gaincontroller (AGC) is fixed as a specific value (S1401).

[0111] Second, the maximum signal power direction is acquired byrotating the antenna direction to 360° (S1 501-S1504). In this case, theantenna pattern counter register 1103 and the antenna directionacquisition register 1106 are renewed. If all the antenna patterns arechecked, the step-1406 is processed. (S1406). The auto gain controlleris fixed at a specific value.

[0112] Fourth, the maximum signal power antenna direction acquisitionvalue is loaded from the maximum signal power register 1105 to theantenna direction acquisition register 1106 and the antenna counterregister 1103 is initialized (S1406).

[0113] Fifth, the antenna acquisition process is finished and theantenna direction tracking process is started (S1407-S1410). In thisinstance, the antenna pattern counter register 1103 is initialized.However, if the channel condition information (i.e., the signal powercondition, SNR information condition) is not satisfied, the maximumsignal power register 1105 is initialized and the VSB demodulator 102 isinitialized for reacquiring the antenna direction and rescanned (S1411).

[0114] 3) Antenna Direction Tracking Controller:

[0115] The antenna tracking controller 103-3 receives the channelinformation (i.e:, such as signal power, multi-channel signal power,SNR) from the channel information detector 103-1, converges the antennadirection from the maximum signal power acquisition location to theoptimal receiving location. When the smart antenna provides only a verysimple antenna pattern, for example, when having a plurality of antennapatterns, the tracking process is omitted.

[0116] However, when the antenna provides a tens of or hundreds ofantenna patterns, effective receiving performance is improved, and theantenna enables to correspond to a channel environment changed everyhour.

[0117] The antenna direction tracking controller 103-3, as illustratedin FIG. 16, includes a signal power tracking error detector 1601, amulti-channel power tracking error detector 1602, a SNR tracking errordetector 1603, an error integrator 1604, and the antenna controlinterface 1605. Hereinafter, the antenna direction tracking controller103-3 is described in more detail.

[0118] 3-1) Signal Power Tracking Error Detector:

[0119]FIG. 17 illustrates a detailed block diagram of a signal powertracking error detector 1601. As illustrated in FIG. 17, the signalpower tracking error detector . 1601 includes a delayer 1701 forcomparing the present antenna convergence direction for the signal powerinformation with the previous convergence direction, a subtractor 1702,a sign assignor 1703 for distinguishing the converged direction byadding a predetermined sign, and a multiplier 1704 and a delayer 1705for outputting the antenna convergence direction according to thecomparison result.

[0120] The signal power tracking error detector 1601 structured asabovementioned regularly receives the signal power information from thechannel information detector 103-1 and outputs the antenna convergencedirection by the change of signal power information according to achange of the antenna direction.

[0121] For example, if the signal power is increased when the antennaconvergence direction is moved clockwise, the antenna convergencedirection is moved one more step clockwise. If the signal power isdecreased, the antenna convergence direction is moved counterclockwise.By repeating said process, the antenna convergence direction informationis outputted to the error integrator 1604.

[0122] 3-2) Multi-Channel Signal Power Tracking Error Detector:

[0123]FIG. 18 illustrates a detailed block diagram of an antennadirection multi-channel signal power tracking error detector 1602 ofwhich the structure is similar to the structure of FIG. 17 and will beomitted. The multi-channel signal power tracking error detector 1602regularly receives SNR information from the channel information detector103-1, watches the change of the multi-channel signal power informationaccording to the antenna direction change, and outputs the antennaconvergence direction.

[0124] For example, if the signal power is increased when the antennaconvergence direction is moved clockwise, the antenna convergencedirection is moved one more step clockwise. If the signal power isdecreased, the antenna convergence direction is moved counterclockwise.By repeating said process, the antenna convergence direction informationis outputted to the error integrator 1604.

[0125] Examples of many tracking error detectors are illustrated in FIG.17 to FIG. 19, and various tracking error detectors to be proposed inthe present invention may be applied. Antenna convergence information ofa plurality of antenna tracking error detector are selectively assembledand employed in the antenna tracking process.

[0126] 3-4) Error Integrator:

[0127]FIG. 20 illustrates a detailed block diagram showing an embodimentof an error integrator 1604. The error integrator 1604 accumulateserrors by receiving and selectively assembling the antenna convergenceinformation from each tracking error detector 1601-1603. The accumulatederror is converged into an optimal antenna direction around the antennadirection of maximum signal power acquisition location.

[0128] Top value of the error accumulated at the error integrator 1604is divided into number of antenna patterns, and converged into theantenna direction. Detailed movement of the error integrator 1604 is asfollows. In an antenna direction acquisition process (i.e., whentrack_en is 0), the signal power acquisition direction is loaded fromthe antenna direction acquisition controller 103-2 and in an antennatracking process (i.e., track_en is 1), the antenna convergencedirection information is accumulated. In this case, the antennaconvergence range is limited according to the reception (i.e., SNR orSER condition). For example, if the reception is not satisfied after theantenna direction acquisition process, the antenna acquisition range isdeviated from the adjacent antenna direction acquisition. If thereception is satisfied, the antenna acquisition convergence range islimited within the antenna direction acquisition location. Purpose ofthe limitation is for preventing the antenna control system from beingdiverged.

[0129] Noap being number of the antenna patterns means a step size ofthe antenna direction. The antenna step size is controlled according tothe antenna direction convergence. In general, in an early convergenceprocess, the step size is enlarged for a fast convergence and decreasedat an optimal convergence location for stabilizing the signal changeresulted form the tracking process.

[0130] 3-5) Antenna Control Interface

[0131] Antenna control interface 1605 means an interface between anantenna control system and a smart control system. The present inventionbasically supports US CEA/EIA 909 standard (a series data transmission)and other various interfaces may be supported. The antenna interfacechanges according to a kind of the smart antenna.

[0132] Meanwhile, the present invention can be applied to an antennasystem in a filed of radio telecommunication such as VSB/OFDM.

[0133] As abovementioned, the digital TV receiving antenna controlsystem has advantages as follows.

[0134] First, a process for controlling the smart antenna is dividedinto an acquisition process and a tracking process, and the trackingprocess is selectively omitted and applied to both a simple and complexsmart antenna.

[0135] Second, in the acquisition process, the maximum signal powerdirection is detected by fixing AGC as a specific value. In other words,a method of indirectly detecting a signal size from the AGC informationof the tuner was conventionally used. However, in the present invention,a method of directly calculating the signal power from an input signalis employed and the method is highly reliable and the detecting speed isvery fast.

[0136] Third, the antenna controller of the present invention not onlyachieves optimal antenna convergence but also corresponds to a channelenvironment changed every hour by selectively assembling various channelinformation and using the information in the tracking process.

[0137] Fourth, it is easy to make in one-chip and integration of thesystem is improved because all controlling portions may be digital andflexibility of the control system is secured because the antenna scanprocess includes software.

[0138] It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A smart antenna control system, comprising: asmart antenna system for forming an antenna pattern suitable for signalreception by receiving mechanical or electrical antenna control signaland controlling a beam width, gain, and frequency characteristic; a VSBdemodulator for generating channel data for demodulating a VSB(Vestigial Side Band) signal received through the smart antenna system,generating channel data for the antenna pattern, and outputting thedemodulated VSB signal in a transport packet form; and an antennacontroller for receiving the channel data and auto gain controlinformation from the VSB demodulator and controlling the smart antennasystem by using the auto gain control information and the channelinformation set as a specific value.
 2. The digital TV receiving smartantenna control system of claim 1, wherein the channel data comprisesthe auto gain control information, demodulated I channel data,phase-tracked I channel data, FEC (forward error correction) error data,and a field sync signal.
 3. The digital TV receiving smart antennacontrol system of claim 1, wherein the VSB demodulator comprises an autogain controller for directly controlling a gain of RF (Radio Frequency)and a gain of IF (Intermediate Frequency) signal.
 4. The digital TVreceiving smart antenna control system of claim 3, wherein the auto gaincontroller comprises: a tuner for tuning the gain of the RF signal byincreasing or decreasing the gain of RF signal according to inputted RFauto gain control signal; an IF auto gain controller for controlling thegain of the IF signal by increasing or decreasing the gain of IF signalaccording to inputted IF auto gain control signal; a VSB receiving chipfor generating the IF auto gain control signal and the RF auto gaincontrol signal by using a reference value of a RF auto gain controlsignal and demodulated passaband or baseband receiving signal, andoutputting the signals to the IF auto gain controller and the tuner. 5.The digital TV receiving smart antenna control system of claim 1,wherein the antenna controller comprises: a channel information detectorfor receiving the channel data from the VSB demodulator and detectingthe channel information so as to determine a predetermined channelcondition; an antenna direction acquisition controller for receiving thechannel information and the channel condition information and acquiringthe antenna direction; an antenna direction tracking controller forreceiving an acquisition signal of the antenna direction acquisitioncontroller and the channel information and converging the antennadirection from a maximum signal power acquisition location to an optimalreceiving location.
 6. The digital TV receiving smart antenna controlsystem of claim 5, wherein the channel information detector comprises: asignal power detector for detecting and outputting the signal powerinformation from I, signal of the passaband or baseband signal, the IFgain, and RF gain in the channel data, and comparing the signal powerinformation with a preset signal power reference value so as to outputthe signal power condition; a multi-channel signal power detector fordetecting and outputting the multi-channel signal power information froman equalizer input I channel data or a field sync signal in the channeldata, and comparing the multi-channel signal power information with thepreset multi-channel signal power reference value so as to output themulti-channel signal power condition; a SNR detector for detecting SNR(signal-to-noise) information from FEC (forward error correction) inputI channel data or field sync signal in the channel data, and comparingthe SNR information with a preset SNR reference value so as to outputSNR condition; and a SER detector for detecting and outputting SER(segment error rate) information from FEC error value in the channeldata, and comparing the SER information with preset SER reference valueso as to output SER condition.
 7. The digital TV receiving smart antennacontrol system of claim 6, wherein the signal power detector receivesand squares the passband or baseband I signal, accumulates the squaredvalue into a predetermined window size, and detects and outputs thesignal power information.
 8. The digital TV receiving smart antennacontrol system of claim 6, wherein signal power detector receives thepassaband or baseband I signal and get an absolute value, accumulatesthe absolute value into a predetermined window size, and detects andoutputs the signal power information.
 9. The digital TV receiving smartantenna control system of claim 6, wherein the multi-channel signalpower detector comprises: a train sequence generator for detecting atrain sequence from the field sync signal (nFSYNC) of a main signal; amultiplier for multiplying an output of the train sequence generatorwith an input signal; an integer extractor for extracting an integerfrom an output of the multiplier; a ghost power formalizer forformalizing and calculating ghost power from the integer extractor. 10.The digital TV receiving smart antenna control system of claim 6,wherein the multi-channel signal power detector comprises: a trainsequence generator for generating a train sequence of a main signal andeach multi-channel signal; a plurality of multipliers for multiplyingthe train sequence of the main and each multi-channel with the inputsignal; an integer extractor for extracting only an integer from eachoutput of the plurality of multiplier; and a ghost power formalizer forformalizing and calculating ghost power from the integer extractor. 11.The digital TV receiving smart antenna control system of claim 6,wherein the SNR detector calculates the a MSE (mean square error) valuefrom the received field sync signal and train sequence, and finding andoutputting SNR information by using MSE value.
 12. The digital TVreceiving smart antenna control system of claim 6, wherein the SNRdetector calculates MSE value from demodulated and equalized I channeldata and decision constellation and obtaining and outputting SNRinformation by using MSE value.
 13. The digital TV receiving smartantenna control system of claim 6, wherein the antenna directionacquisition controller continuously determines whether to proceed theantenna direction tracking process by selectively assembling channelcondition information outputted from the channel information detector orto repeat the antenna direction reacquisition process, and receivesSYNCLOCK signals before EQ and before FEC and determines aninitialization of the channel equalization.
 14. The digital TV receivingsmart antenna control system of claim 6, wherein antenna directionacquisition controller rotates the antenna direction 360° for confirmingwhether a receiving signal exists by controlling the smart antennasystem, and rotates the antenna 360° from the antenna direction havingthe receiving signal for acquiring the maximum signal power direction soas to start the antenna tracking process.
 15. The digital TV receivingsmart antenna control system of claim 6, wherein the antenna directionacquisition controller comprises: an antenna scan processor forreceiving the signal power channel condition information from thechannel information detector and outputting necessary control signals; atimer for calculating delay time in each process of the antenna scanprocessor; an antenna pattern count register for counting pattern numberof the smart antenna in the antenna direction acquisition process; asignal power register for storing the signal power information; amaximum signal power register for storing the maximum signal power valueand the antenna direction; and an antenna direction register for storingthe antenna direction information.
 16. The digital TV receiving smartantenna control system of claim 4, wherein the antenna directiontracking controller comprises: a signal power tracking error detectorfor regularly receiving the signal power information from the channelinformation detector, and outputting the antenna convergence directionby observing a signal power change according to the antenna directionchange; a multi-channel signal power tracking error detector forregularly receiving the multi-channel signal power information from thechannel information detector, and outputting the antenna convergencedirection by observing a multi-channel signal power change according tothe antenna direction change; a SNR tracking error detector forregularly receiving SNR information from the channel informationdetector and outputting the antenna convergence direction by observing amulti-channel signal power change according to the antenna directionchange; and an error integrator for accumulating errors by selectivelyassembling the antenna convergence information of the tracking errordetector, and outputting the antenna control signal so as to convergethe accumulated error to an optimal antenna direction around the antennadirection of the maximum signal power acquisition location.
 17. Adigital TV receiving smart antenna control system, comprising: the smartantenna system forming an optimal antenna pattern for a signal receptionby controlling the antenna through an antenna control signal; a tunerfor tuning only a specific RF signal in RF (Radio Frequency) signalreceived through a smart antenna system, and converting the signal intoan IF signal after automatically controlling RF gain tuned according toRF gain control signal; a VSB (Vestigial Side Band) demodulator fordemodulating after controlling the IF (Intermediate Frequency) signalgain according to IF gain control signal; a channel information detectorfor detecting channel information such as signal power, multi-channelsignal power, SNR (signal-to-noise ratio), and SER (Segment Error Rate)outputted from the VSB demodulator, determining the channel conditionand outputting the channel information and the channel conditions; andan antenna direction acquisition controller for receiving signal powercondition, multi-channel signal power condition, SNR condition, SERcondition, and signal power information form the channel informationdetector and detecting and outputting an antenna direction of themaximum signal power, fixing the RF gain control signal and IF gaincontrol signal in acquisition process, and changing the signalsaccording to the receiving signal in a tracking process.
 18. The digitalTV receiving smart antenna control system of claim 17, wherein thechannel information detector comprises: a signal power detector forreceiving passband and baseband I signal from the VSB demodulator,detecting the signal power information, and comparing the signal powerinformation with the signal power reference value so as to output thepower condition; a multi-channel signal power detector for receiving Ichannel data or a field sync signal equalized at the VSB demodulator,detecting multi-channel signal power information, and comparing themulti-channel signal power information with a preset multi-channelsignal power reference value so as to output the multi-channel signalpower condition; a SNR detector for receiving I data or field syncsignal detecting SNR (signal-to-noise) information from FEC (forwarderror correction) input I channel data or field sync signal in thechannel data, and comparing the SNR information with a preset SNRreference value so as to output SNR condition; and a SER detector fordetecting and outputting SER (segment error rate) information from FECerror value in the channel data, and comparing the SER information withpreset SER reference value so as to output SER condition.
 19. Thedigital TV receiving smart antenna control system of claim 18, whereinthe signal power detector comprises: a squaring operator for receivingpassband and baseband I signal from the VSB demodulator; and anintegrator for accumulating the squared value in a predetermined windowsize and detecting the signal power.
 20. The digital TV receiving smartantenna control system of claim 18, wherein the signal power detectorcomprises: an absolute operator for receiving the passband and basebandI signal from the VSB demodulator; and an integrator for accumulatingthe absolute value in a predetermined window size and detecting thesignal power.
 21. The digital TV receiving smart antenna control systemof claim 18, wherein the multi-channel signal power detector detects themulti-channel power information based on a correlation value of thefield sync section when the multi-channel does not exist by using thefield sync section of a main signal.
 22. The digital TV receiving smartantenna control system of claim 18, wherein the multi-channel signalpower information detector detects the correlation value by using fieldsection of a primary multi-channel signals and a field section of themain signal, and detecting the multi-channel power information.
 23. Thedigital TV receiving smart antenna control system of claim 18, whereinthe SNR detector squares difference of the field sync signal andtraining sequence included in demodulated receiving signal, accumulatesthe calculation, and calculates an average to obtain MSE so as to applythe MSE value and detect SNR.
 24. The digital TV receiving smart antennacontrol system of claim 18, wherein the SNR detector calculates MSE ofreceived signal by squaring difference between the demodulated receivingsignal and decision constellation, accumulates the calculation, detectsSNR by applying the MSE value.
 25. The digital TV receiving smartantenna control system of claim 18, wherein antenna directionacquisition controller determines whether to proceed the antennadirection tracking process by selectively assembling the signal powerinformation, multi-channel signal power condition information, SNRcondition information, and SER condition information outputted from thechannel information detector or to repeat the antenna directionreacquisition process, and receives SNCLOCK signals before EQ and beforeFEC, and determines an initialization of the channel equalization. 26.The digital TV receiving smart antenna control system of claim 17,wherein the antenna acquisition controller confirms whether thereceiving signal exists by controlling the smart antenna system androtating the antenna direction, and acquires the maximum signal powerdirection by rotating the antenna 360° from the antenna direction havingthe receiving signal so as to start the antenna tracking process. 27.The digital TV receiving smart antenna control system of claim 17,wherein the antenna direction acquisition controller comprises: anantenna scan processor for receiving the signal power channel conditioninformation from the channel information detector and outputtingnecessary control signals; a timer for calculating delay time in eachprocess of the antenna scan processor; an antenna pattern count registerfor counting pattern number of the smart antenna in the antennadirection acquisition process; a signal power register for storing thesignal power information; a maximum signal power register for storingthe maximum signal power value and the antenna direction; and an antennadirection register for storing the antenna direction information. 28.The digital TV receiving smart antenna control system of claim 17,further comprising an antenna direction tracking controller forreceiving signal power information, multi-channel signal powerinformation, SNR information from the channel information detector,generating an antenna control signal, outputting the signal to the smartantenna system, and converging the antenna direction from the maximumsignal power acquisition location to the optimal receiving location. 29.The digital TV receiving smart antenna control system of claim 28,wherein the antenna direction tracking controller comprises: a signalpower tracking error detector for regularly receiving the signal powerinformation from the channel information detector, and outputting theantenna convergence direction by observing a signal power changeaccording to the antenna direction change; a multi-channel signal powertracking error detector for regularly receiving the multi-channel signalpower information from the channel information detector, and outputtingthe antenna convergence direction by observing a multi-channel signalpower change according to the antenna direction change; a SNR trackingerror detector for regularly receiving SNR information from the channelinformation detector and outputting the antenna convergence direction byobserving a multi-channel signal power change according to the antennadirection change; and an error integrator for accumulating errors byselectively assembling the antenna convergence information of thetracking error detector, and outputting the antenna control signal so asto converge the accumulated error to an optimal antenna direction aroundthe antenna direction of the maximum signal power acquisition location.30. The digital TV receiving smart antenna control system of claim 28,wherein the top value of an error accumulated to the error integrator isdivided and converged into the antenna direction.
 31. A method forcontrolling a digital TV receiving smart antenna, comprising the stepsof: (a) acquiring maximum signal power according to the antennadirection by using signal power information, multi-channel information,SNR information, and SER information extracted from an input signal; and(b) converging the smart antenna into an optimal reception byselectively assembling the signal power information, the multi-channelinformation, the SNR information, and the SER information.
 32. Themethod for controlling a digital TV receiving smart antenna of claim 31,wherein the step (a) comprises calculating the signal power according tothe antenna direction by fixing the auto gain control value as aspecific value and detecting the maximum signal power.
 33. The methodfor controlling a digital TV receiving smart antenna of claim 31,wherein the step (a) comprises: (c) fixing the auto gain control valueas a specific value; (d) confirming whether the receiving signal existsby rotating the antenna direction; (e) acquiring the maximum signalpower direction by rotating the antenna 360 ° from a direction of thereceiving signal; and (f) directing antenna tracking after acquiring themaximum signal power direction.
 34. The method for controlling a digitalTV receiving smart antenna of claim 31, further comprising the steps of:(g) watching whether the reception is good by referring the channelcondition information; and (h) starting reacquisition process if thereception is not good.